

public class Tree {


    public static class TreeNode {
        int value;
        TreeNode left;
        TreeNode right;

        public TreeNode(int value) {
            this.value = value;
        }
    }

    public static TreeNode root;

    private int nodeCount;

    public Tree() {
        TreeNode node1 = new TreeNode(1);
        TreeNode node2 = new TreeNode(2);
        TreeNode node3 = new TreeNode(3);
        TreeNode node4 = new TreeNode(4);
        TreeNode node5 = new TreeNode(5);
        TreeNode node6 = new TreeNode(6);
        TreeNode node7 = new TreeNode(7);

        root = node1;
        node1.left = node2;
        node1.right = node3;
        node2.left = node4;
        node2.right = node5;
        node3.left = node6;
        node3.right = node7;

    }


    public void preOrder(TreeNode node) {
        if(node == null) {
            return;
        }

        System.out.print(node.value + " ");
        nodeCount ++ ;
        preOrder(node.left);
        preOrder(node.right);
    }

    public int size(TreeNode node) {
        preOrder(node);
        return nodeCount;
    }

    public int size1(TreeNode node) {
        if (node == null) {
            return 0;
        }

        return size1(node.left) + size1(node.right) + 1;
    }

}




